Well, no, I don’t think I would ever stop modeling steam, especially with locos as good as they are now.
Back in the 60’s and 70’s you might have had a point here, but not now.
I would suggest that many people have problems with steam for two reasons - poor trackwork and curves and turnouts that are too sharp for the locos they buy.
My curves are 36" radius and above. Any turnout that a mainline size steam loco runs on is #6 or larger.
All my curves have easements. All my grades are smoothly transitioned into.
And even with those track standards I restrict the rigid wheel base of the steam locos I buy to about 20 scale feet. I only have one exception, I do have one Spectrum USRA 2-10-2 which has a rigid wheelbase of 21’.
This means no 2-12-2’s, or 80" drivered 4-8-4’s like a GS4, or similar monsters of the rails.
As Crandel pointed out, modern long wheelbase diesels with 3 or4 axle trucks can be just as problematic as any steam loco.
All my diesels are 1st generation and most ride on B-B trucks.
Are model steam locos a little “fussy” - YES - just read again my post about “improving Bachmann locos”. Are they always perfect out of the box - no, but a lot of diesels aren’t either. But for me, those little details, once worked out, are never a problem later.
A little extra tender weight, a slighly improved drawbar, some BullFrogSnot or extra weight for pulling power - no big deal, just part of the fun for me.
I like diesels too, an ABBA set of Alco FA’s is a cool sight at the head of a 50 car freight train - but so are three Spectrum 2-8-0’s or a pair of heavy Mountains.
Sheldon